Method of printing



Oct. 21, 1952 BRODIE 2,614,493

METHOD OF PRINTING Filed April 2, 1946 INVEN'IOR.

GEORGE R. BRODIE [2 M QMMLQ 6.4%

ATTORNEYS Patented Oct. 21, 1952 2,614,493 METHOD OF PRINTING George "Rogers Brodie, Lower Merion Township, --Montgomery Gounty, Pa., assignor to Fredk'H.

I ,Levey' 00., Inc., New York, N.

' .ofNeW York 1 a corporation Application April 2, 1946,'Serial No. 658,953 claims. (01. 101-426) I H 1 r .This-inven-tion-relates to .azmeth-od of'printing and. -:particularly 1 to an improved procedure in printing rsuccessivfely on opposite sides ofa web or sheet,;avoiding1ofisettingof the'first impression when-fithesecond impression is made. Heretofore,warious methods'of accomplishing the de siredcresult have beendeveloped, the most widely useidabeing the heating of the web or sheet after thei impression has been:made=to rapidly dissipate the :volatile solvent of the ink. l Such procedurezhas" beenv employedggenerally in the printing Off magazines, the pressesused for thatpurpose being so constructed as to permit the introduction of steam drums; radiant heaters or otheriheating units 'There, are other types .of *printing "presses, notably newspaperjpresses and rollfedsheet delivery presses which, because of construction problems, cannot be fitted with heating :means adapted to increase theitemperatureof thepaper after theflrstzor-secondimpression. I V

ItJ-isthe object of the present-inventionmto providean improved: method of printing whereby the' desired result of substantially instantaneous drying of each i impressiontcan ,be accomplished readily.

-'..-Other objects:;and advantages of the invention will be apparent as it .is better understoodby reference t-o the following specification and the made and: the? impression is therefore immediately dry enough to permit-second side printing-without offset. The upp-erlimit of 400 F. is merely indicative of a temperature above which many types of paperare like'lyto discolor or char. Obviously, the temperature must be kept below the point OfTdiSCOlOIfit-iOIL At the'same time, sufiicient heat mustbe retained in the paper ,toefiect the evaporation of; the solvent employed in the ink; Heatingofthe paper may be accomplished. in

any suitable manner, for; example by;conveying it aroundasteam heateddrumwhich is maintained at the temperature desired. In ,many .cases. it"

l 2 may be desirable to surround the .drum with a hood and to circulate heated 'air through the hood :in order to bring the paper quickly to-z-the desired temperature. The heating may be -ac complished similarly by means of radiant .heate'rs'such as .have'been employed heretofore-in the,

drying of printed, impressions'on paper webs'and sheets. In order to attain the desired object, it is desirable also that the ;plate and impression cylinders ,of the pressbe cooled by a-circulating medium such as water and maintained atadesirable temperature which may :be-atmospheric temperature or lower. The wateniorexample,

may be maintainedin asuitable tank andheated or cooled to the desiredtemperature by circulating a cooling or heating .medium through-acoil disposed in thetank. The water, may be delivered tov the press by a pump and returned to the tank Various types of inks may be employed. I preferinksconsisting of a pigment in a suitable vehiclercomprising a resin anda solvent therefor having a vaporpressure "such that the ink remains stable on the ink distributing system, the solvent being .vaporized rapidly when the ink is subjected to elevated temperatures. are described in detail in the patent toGessler No.'2,087,190. Such inks-are well known in the art, and the following examples will serve to i1- lustrate suitable. formulations which, however, are subject to wide variations, in so far as the applica-. tion of thepresent inventionis concerned,

Emam'ple I Carbon black i Rosin modified with an alpha-beta unsaturated dicarboxylic acid"; "20.0

Propylene glycol 6310 1 1oo;o Example II Carbon black '1'7i0 Limed or zincated rosin 33.0 Non-aromatic petroleum fraction boiling from 441 more F The web-isconducted. thenrimmediatelyto the second plate and impression cylinders; where; itlis Such inks printed on the reverse side. The heat still remaining in the paper is sufficient to vaporize the solvent, thus affording a dry second impression. Owing to the cooling of the plate and impression cylinders, the latter are not permitted to attain any dangerously high temperature, and the web is sufficiently cooled so that it may be cut into sheets in the usual manner and handled by the pressman.

While the invention will be described in more detail hereafter in a web perfecting press, it is equally applicable to roll fed sheet delivery presses in which the paper is heated while in web form and thereafter formed into sheets by guillotine cylinders, after which the sheets are conveyed by the usual mechanism commonly used for that purpose successively to the first and second plate and impression cylinders, so that the sheets are printed onboth sides, the ink being dried substantially instantaneously by the heat carried in the paper.

Referring to the drawing, 5 and 6 indicate impression cylinders, and I and 8 plate cylinders which are mounted in the usual manner to rotate as the web 9 isfed over an idler I0, between the cylinders 5 and I, over an idler II, and thence between the cylinders 6 and 8 to receive the first and second side impressions. The plate cylinder 1 is supplied with ink through the usual rollers I2 forming a part of the ink feed system, and the plate cylinder 8 is similarly supplied with ink through the rollers [3.

The web is supplied from a mill roll M which is mounted for rotation and passes over idlers l5 and It to a heating drum '11 which is mounted for rotation and is adaptedto be supplied with steam from any suitable source in order to maintain the periphery of the drum at the desired temperature. A housing 18 surrounds the drum I! and is adapted to be supplied through an inlet IS with a blast of air which may be heated in any suitable equipment and directed by a blower through the housing and about the periphery of the drum H. The heated air escapes through an outlet 20. The web passes around an idler 2| and is directed to the idler ID.

The heating arrangement or some equivalent arrangement such as radiant burners is adapted to bring the temperature of the web to the point desired, which preferably is about 300-325 F., although lower or higher temperatures may be used. At such temperatures the heat carried by the web to the plate cylinders is, as I have found, sufficient to dry the inked impression substantially instantaneously. Obviously the rate of drying will depend to some extent upon the nature of the solvents employed in the ink, and higher or lower temperatures in the web will be employed depending upon the vaporizing characteristics of the ink solvents. Likewise the speed of operation may vary, and lower temperatures may be employed at lower speeds.

The cooling of the plate and impression cylinders may be effected by providing a tank 22 in which a coil 23 is disposed to permit heating or cooling of the fluid such as water maintained in the tank. A pump 25 permits circulation of the cooling medium from the tank 22 through pipes 25 and 26 to the impression and plate cylinders 5, 6, I and 8. The cooling fluid returns through pipes 2'! and 28 to the tank 22.

In accordance with the invention, effective drying of the inked impressions permitting sec-' ond side printing without oifset is accomplished in an economical and satisfactory manner. The

by plate and impression cylinders which comprises heating the sheet material, applying to the heated sheet material the impression of an ink comprising'a coloring agent and a vehicle containing a thickening agent and a solvent therefor having a sufiiciently low vapor pressure to make the ink stable under normal press room printing conditions but capable of rapid vaporization solely by the application of heat, the heating of the sheet material prior to the application of the ink impression being to an elevated temperature below the point at which discoloration thereof usually occursbut to atemperature sufllciently high that the heat still carried by the sheet material at the time of the application of the ink impression thereto is sufiicient to rapidlyvaporize the solvent from the ink and leave a dry impression, and cooling the plate cylinder to prevent its overheating and the setting-up of the ink thereon.

2. The method of printing set forth in claim 1 in which the sheet material is heated prior to the application of the ink impression thereto to a temperature between 225 F. and 400 F.

3. The method of printing set forth in claim 1 in which the sheet material is heated prior to the application of the ink impression thereto to a temperature between 300 F. and 325 F.

4. The method of printing on sheet material in which the application of the ink thereon is by plate and impression cylinders which comprises maintaining the sheet material in heat-exchange relation with a heating means until it is heated to an elevated temperature, passing the heated sheet material from such heat-exchange relation to the heating means to a printing zone, apply ing to the heated sheet-material at said printing zone the impression of an ink compris-' ing a coloring agent and a vehicle containing a thickening agent and a solvent therefor having a sufficiently low vapor pressure to make the ink stable under normal press room printing conditions but capable of rapid vaporization solely by the application of heat, the elevated temperature to which the sheet material is heated while in heat-exchange relation with the heat-' ing means being below that at which discolora tion of the sheet material would occur but suf-" ficiently high that the heat still carried by the sheet material at the time of application of the ink impression thereto is sufiicient to rapidly vaporize the solvent from the ink and leave a dry impression, and cooling the plate cylinder to prevent its overheating and 'the'setting-up of the ink thereon.

5; The method of printing on sheet material in which the application of the ink thereon is by plate and impression cylinders which comprises heating the sheet material and applying to the heated sheet material the impression of an ink comprising a coloring agent and a vehicle con-" jtaining a' thickening agentand a solvent there- 5 for having a sufficiently low vapor pressure to make the ink stable under normal press room printing conditions but capable of rapid vaporization solely by the application of heat, and applying a similar ink impression on the reverse side of the sheet material, the heating of the sheet material prior to the application of the first ink impression thereto being to an elevated tempera- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,037,965 Mortimer Sept. 10, 1912 1,569,296 Odell Jan. 12, 1926 1,681,603 Wilhelm Aug. 21, 1928 2,070,278 Kelly Feb. 9, 1937 2,087,190 Gessler July 13., 1937 2,298,803 Morris Oct. 13, 1942 2,322,445 Huber June 22, 1943 2,329,152 Br'eyer Sept. '7, 1943 

